I use data sets of weather variables in my statistics courses. There are tons of those variables in Wikipedia. To find weather variables in the city of Melbourne, for instance, just type in your browser: "wikipedia Melbourne", then go to "climate". You will find a table of weather variables, they are provided under the Creative Commons Attribution-ShareAlike License. If you want more detailed data just follow the link from wikipedia to the original source. In the case of Melbourne the "climate" table indicates that it is sourced from the "Bureau of Meteorology" and again these data sets from the Bureau are publicly available and hence you or your students can download them with no problem.
Similarly for weather data in the city of Buenos Aires, just type in your browser "wikipedia Buenos Aires" and then go to "climate". The source of the data, 'wikipedia' tells us, is the SMN (Servicio Meteorologico Nacional) which releases these data for public use.
A Google search on yields lots of useful looking hits. You could add your discipline (e.g., psychology, sociology, whatever) as another search term to narrow the field a bit. HTH.